and another way by polling interrupt flag.
Code:
    ' RB0 interrupt
    ' =============
    '
    ' File name : RB0.bas
    ' Company : Mister E 
    ' Programmer : Steve Monfette
    ' Date : 03/05/2005
    ' Device : PIC16F628


    '
    '    PIC setting
    '    ===========
         '
         ' Using MPASM to compile the code to target device
         '
         '
@ __config _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _LVP_OFF & _BODEN_ON 
         ' Internal Oscillator
         ' Enable watch dog timer
         ' Enable power up timer
         ' Disable MCLR pin
         ' Disable low voltage programming
         ' Enable brown out detect


    '
    '    Hardware definition
    '    ===================
         '
         '
         TRISB = %00000001   ' RB0 as input, other as output
                             ' Push button between RB0 & ground
    
    '
    '    I/O Alias definition
    '    ====================
         '
         '
         RB0LED              var   PORTB.6
         MainLoopLED         var   PORTB.7

         
    '
    '    Interrupt Definition
    '    ====================
         '
         '
         OPTION_REG = 0      ' Enable pull-up on PORTB
                             ' RB0 interrupt on falling edge
                             

    '
    '    Variable definition
    '    ===================
         '
         '
         Delay              var word
         
         
    '
    '    MainLoop
    '    ========
         '
         '
Start:
     '
     '
    Toggle mainloopled
    for Delay = 1 to 500    ' delay loop 500ms
        pause 1             ' using 1 ms delay to avoid latency
        if INTCON.1 then    ' test RB0 interrupt flag
           rb0led=RB0LED ^1 ' toggle RB0LED status
           INTCON.1=0       ' reset interrupt flag
           endif
        next                 
    goto start              ' do it forever